1. Field
One embodiment of this invention relates to a head gimbal assembly used in a disk drive comprising a disk as a recording medium and the disk drive provided with the same.
2. Description of the Related Art
In recent years, disk drives, such as magnetic disk drives, optical disc drives, etc., have been widely used as external recording devices of computers or image recording apparatuses.
A disk drive, e.g., a magnetic disk drive, generally comprises a magnetic disk, spindle motor, head actuator, voice coil motor (VCM), circuit board unit, etc. The spindle motor supports and rotates the disk in a case. The head actuator supports a magnetic head. The VCM drives the head actuator.
The head actuator comprises a bearing and arms laminated to and extending from the bearing. The magnetic head is mounted on each arm by means of a suspension.
The circuit board unit integrally comprises a base portion, on which a head IC, connectors, etc., are mounted, and a main flexible printed circuit board (main FPC) extending from the base portion to the vicinity of the bearing. An extended end portion of the main FPC forms a plurality of terminal areas, and a plurality of connection pads are arranged on each terminal area. The terminal areas are attached to the bearing of the head actuator by screws.
A flexure comprising a conductor pattern and terminals is attached to the suspension and each arm of the head actuator. One end of the flexure is connected to the magnetic head, and the other end to its corresponding terminal area of the main FPC. Thus, the head is electrically connected to the circuit board unit through the flexure and main FPC.
Terminal portions at the terminal area of the flexure are known to be formed as flying leads, the obverse and reverse surfaces of which are exposed through insulating layers (e.g., Jpn. Pat. Appln. KOKAI Publications Nos. 2006-49751, and 2008198738), in order to reduce the installation space for the flexure to meet the recent trend toward smaller and thinner magnetic disk drives. The exposed terminal portions are soldered to the connection pads of the main FPC. In order to strengthen the terminal portions to prevent their breaking, tin-alloy layers or lining portions are provided on the upper surface and two opposite side surfaces of each terminal portion.
Electrostatic breakdown of magnetic heads is a major problem in quality of the magnetic disk drives constructed in this manner. In soldering each terminal portion or flying lead to the terminal area of the main FPC or repairing them, for example, a soldering iron is applied to a conductor layer of the terminal portion to melt it. If this is done, however, static electricity may be produced and cause electrostatic breakdown.